Suds containers made of plastic for washing machines are known, said containers being in the form of a cylindrical vessel that surrounds the drum. Here, a metallic bearing block with a hub to receive a drive shaft for the drum is integrated into the plastic compound in one of the front walls. The encapsulation of the metallic bearing block by injection molding gives rise to considerable intrinsic stresses in the suds container resulting from the fact that the plastic cools off from the hardening temperature down to room temperature, shrinking in the process. Forces caused by the different shrinkage behavior of the plastic in comparison to the metal part exert such a strong effect on the bearing block that the suds container can become deformed, at least in some areas. This has a detrimental impact on the homogeneity of the suds container so that stress peaks can give rise to hairline cracks that are particularly responsible for greatly reducing the service life of a suds container created in this manner.
EP 1 240 376 B1 describes a suds container, and in this embodiment, a so-called stand support part is laid into the injection mold. Then the part is encapsulated in the mold with an especially fiberglass-reinforced plastic in such a way that the metallic part is embedded at least almost completely into the material of the front surface. When such an injection-molded part cools off, the different materials give rise to shrinkage stresses that can cause the above-mentioned hairline cracks in the material.
Another technique known for the production of a suds container made of plastic is described in GB 2 333 300 A, in which radial ribs are formed around the receiving area of the hub, which is likewise integrated into the plastic compound so that said ribs, together with rings, form an additionally reinforcing truss-like profile in the bearing block area.
The problem that arises despite the use of a fiberglass-reinforced plastic is that these hairline cracks nevertheless occur, particularly in the integration area of the metallic bearing block or of the hub, especially at the boundary between the plastic and the metal, which translates into a shortened service life for the suds container. Moreover, the price of fiberglass-reinforced plastics for suds containers is very high. Inexpensive, non-reinforced plastics are not suitable for use under the requisite mechanical and thermal loads. In addition to this main problem, reinforced plastics also entail drawbacks, namely, the fact that they display anisotropic material behavior because the fiber-matrix coupling is extremely problematic because of the very short fibers and the different orientation of the fibers. Aside from the shortened service life, the mechanical strength and the thermal strength are likewise limited.